I do not think that Spooks will have a second building explosion similar to the one in 8.8. If there is an explosion both of them would die. Spooks seem to specialize in different types of death.

I am more concerned that Ruth might have been hurt by the Russians in revenge against Harry. We know how merciless the Russian mafia or the FBS are. Remember 2.4. I still shudder at their method of killing. I do not think that Ruth will suffer the horrible fate of Jo at the hands of the Redbacks. It has been done before and Spooks would not dare hurt one of our two favorite characters in such way.

I think that Harry was married when he entered MI-6. Wasn't he in MI-6 before joining MI-5 as Head of Section D? He married while he was in the military. He would say it is the adrenaline after an operation that encourages flings. Affairs seem either a perk or curse of spying. After all, in 2.4 he encouraged Danny to sleep with Maxim to get some information. He was a bad boy when he had an affair with Juliet, who was his boss, while both were married.

It finally catches up with him and unfortunately it is possible that Ruth will pay the price for it. I think that is why we see Harry crying in his office.